In the past, passive devices such as inductors, capacitors and resistors were combined with active devices such as diodes and transistors on a printed circuit board to manufacture electronic circuits and/or electronic systems.
As the technology developed, active devices of various types such as bipolar and MOS (or unipolar) devices became integrated into a single semiconductor chip. Integration of these active devices and also passive devices such as resistors and capacitors into a single semiconductor chip led to the formation of electrical circuits in a single semiconductor chip which became known as an integrated circuit semiconductor chip.
Packaging of such integrated circuit semiconductor chips became very important. As a result, integrated circuit semiconductor chip manufacturers have sought for ways to inexpensively and reliably package integrated circuit semiconductor chips.
One early packaging technique was to provide hybrid packages which usually incorporated integrated circuit semiconductor chips with passive devices such as capacitors and resistors on a ceramic substrate surface of a ceramic package which would have metal pins to permit the ceramic package to be inserted into via holes in a printed circuit board containing a number of such ceramic packages interconnected to provide either an electronic circuit or electronic system. Ceramic packages were very costly resulting in higher costs for a printed circuit board using multiple ceramic packages.
In an effort to significantly reduce manufacturing costs, lead frame packages were developed to protectively house integrated circuit semiconductor chips. A lead frame package generally comprised a metal lead frame member that would carry an integrated circuit semiconductor chip on a portion thereof. Wirebonding techniques were used to electrically connect terminal portions or pads of the integrated circuit semiconductor chip to fingers of the lead frame structure. Subsequently, the integrated circuit semiconductor chip on the lead frame structure with its wirebond connections thereto was encapsulated with plastic to provide a plastic encapsulated lead frame package. From a manufacturing cost point of view, plastic encapsulated lead frame packages were very inexpensive as compared to, for example, ceramic type packages.
A need existed to develop electronic type products that would be relatively inexpensive to make and that would take advantage of the lead frame manufacturing technology. Specifically, a need existed for improved lead frame type products that could perform functions that were not provided by the available lead frame products.